La Nan, the Kachin Independence Organization (KIO) spokesman told VOA Burmese the offensive began Saturday and escalated as government troops used artillery and airstrikes outside the town of Mohnyin in Kachin State.

“The assault escalated yesterday (Sunday) after they started invading our smaller bases on November 14, and today they used airstrikes, apparently launching a major offensive. But we have no communication or talks on the matter so far,” La Nan said.

Witnesses also said that fighter jets and helicopters were being used in the bombardment near the town.

One local resident, who did not want to be named, told VOA, “We can see aircrafts flying in the sky and the whole Mohnyin town can see it clearly. We saw bombarding, but couldn’t see the explosions as they were dropped behind mountains."

No causalities were reported from the latest clashes.

KIO was not one of the signatories of a so-called nationwide cease-fire agreement between the government and eight ethnic armed groups reached on October 15.

The KIO spokesman said his group has not had communication with the military regarding the latest clashes.

Other groups reportedly targeted

Another ethnic rebel group in eastern Myanmar also claimed government troops launched airstrikes in a further escalation of fighting with ethnic rebels in central Shan State.

Colonel Sai La of Shan State Army told VOA Burmese “the heaviest attack” in recent clashes began early Monday and continued until evening.

“Six helicopters and three jet fighters were used in heavy assaults with bombardments and gunfire. Today’s attack is the heaviest,” Sai La said.

Myanmar's military blamed the rebels in recent weeks for starting the clashes. The government troops have been engaging in clashes with the Shan State Army, which also refused to sign cease-fire deal with the government.

Ying Hanghpa of Shan Human Rights Foundation told VOA Burmese thousands of civilians have been forced to flee the conflict.

“The latest clashes forced more than 2,000 people (from their homes), reaching a total of more than 8,000 to nearly 9,000,” Ying Hanghpa said.

About 40 percent of the population of Myanmar, also known as Burma, are members of ethnic groups, many of them with longstanding demands for control over natural resources in their territories.